PROMPT

The prompt during raw Lisp breaks is, with most Common Lisp implementations,
adjusted by ACL2 to include the string "[RAW LISP"], in order to
reminder users not to submit ACL2 forms there; see breaks. For Lisps that
seem to use the same code for printing prompts at the top-level as in
breaks, the top-level prompt is similarly adjusted. For Lisps with the
above prompt adjustment, The following forms may be executed in raw Lisp
(i.e., after typing :q).

(install-new-raw-prompt) ; install prompt with [RAW LISP] as described above
(install-old-raw-prompt) ; revert to original prompt from host Common Lisp